


How to Dom Properly (Invisible Chains excerpt)

by adultartist88



Category: Undertale (Video Game)
Genre: BDSM kink, Ecto-Genitalia (Undertale), Foursome - M/M/M/M, Geno likes it rough, M/M, Other, Really rough, Teaching a new dom, references to past sexual and physical abuse
Language: English
Status: Completed
Published: 2020-03-19
Updated: 2020-03-19
Packaged: 2021-02-26 15:17:52
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,248
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23202163
Author URL: https://archiveofourown.org/users/adultartist88/pseuds/adultartist88
Summary: Slim and partner Stretch teach Hacker how to pleasure his new boyfriend and ruler. Hacker doesn't fully realize what he's in for until the whip starts to draw blood. Luckily for Geno, it takes a lot to make the little skeleton turn and run.
Relationships: AfterTech, Honeybbq - Relationship, Papcest, sanscest
Comments: 4
Kudos: 25





	How to Dom Properly (Invisible Chains excerpt)

**Author's Note:**

> All is consensual, although Geno isn't on the greatest terms with Stretch or Slim beforehand. Safewords and sub drop are explained briefly, but the bulk of the conversation happens outside of the written scenes. Make sure you play safely, everyone.
> 
> TW: References to the previous king sexually abusing and extorting Hacker, but there aren't any details or descriptions.

Hacker wanted to like the whip. He saw the occasional glances Geno would cast at it. Of course, it was unlike the broad-shouldered skeleton to ever ask for anything from his goddess. He worshipped the ground Hacker walked on, although to this day, Hacker was still unsure why. Hacker knew Geno was interested but would never bring it up. So Hacker brought it up first. He watched until Geno's gaze wandered over to it in the dim candlelight as they prepared for bed.

"He... used to punish me with that."

Geno jolts at the words, as if embarrassed to be caught thinking about it. Hacker keeps going.

"I always hated it... It hurt so much... But I... I feel like, in the right hands, maybe it wouldn't be so bad?"

He watches Geno gulp, mustering the urge to speak. And then, "It, uh... can certainly be a fun time."

Hacker can't help it- he imagines Geno wielding that whip the way his previous king did. The image makes him shudder. Geno is far too gentle for that. The larger skeleton shifts awkwardly on the edge of the bed, and Hacker can tell he's gathering his courage again.

"If... If you're interested, you could... use it on me."

Oh. That somehow makes a lot more sense. Hacker now imagines his strong and sturdy boyfriend tied and helpless while the whip brings screams of pleasure and pain out of him. It's Hacker's turn to gulp.

"I... don't really know how, Geno..."

Geno rubs the back of his skull, "I think I may know who to ask..."

~~~~~~~~~~~~~

  


"Strip."

Hacker is immediately impressed by the commanding tone of Slim's voice. He also notices the shiver it pulls out of Geno as the well-built skeleton complies without question. Hacker runs over everything Slim briefed him on while they wait- the importance of safewords and trust in a BDSM relationship, how imperative it is that you learn to read your partner even without them, and of course the value of going just a bit outside of your comfort zone just to experiment. His head is spinning, his soul beating nervously, but Slim assured him that a session with him in the lead and his lover helping as well would make everything more clear. Geno agreed.

"Good boy." It's almost a purr this time. Geno shivers again as Slim slowly steps forward. Hacker can't help but compare it to a predator stalking a tasty morsel. "Geno," the taller skeleton drawls, "tell me. Do you enjoy pain?" Geno nods, his face burning crimson. But Slim tuts, "Words, Geno. I need to hear you say it. Do you enjoy pain?"

Geno takes a shaky breath and replies, "Y-yes."

"Yes, what?" There's a threat implied in those words. Hacker doesn't have to see Slim's face to know he's glaring dangerously.

"Y-yes, sir!" Geno corrects hastily.

Slim purrs again, "Good. And do you enjoy being tied up? Helpless and unable to move?"

Another shiver, "Y-yes, s-sir."

Hacker's magic is already pooling in his pelvis just from watching his boyfriend getting worked up. Heavens, they haven't even started yet! He watches with great interest as Slim stands toe-to-toe with his king.

"I'm going to tie you up and beat you until you beg for mercy."

Geno shudders hard from head to toe, "Y-yes, please, sir."

Hacker's soul does a somersault. Geno's expression is a mixture of fear and excitement that Hacker's never really seen before. He glances to their last partner, who has yet to speak. Stretch is the picture of relaxed, watching his lover take control with admiration. If Stretch isn't worried, Hacker decides, he shouldn't be either. He quells his misgivings and returns to paying attention. Slim has brought the heavy chain down from the spool on the rafters and is considering Geno with an evil smirk.

"Hands above your head. Wrists together."

"Yes, sir." Geno's obedience is immediate. He twitches as the taller skeleton tightens the worn leather cuffs around the tiny, delicate bones of each wrist. Slim retracts the chain until Geno's arms are raised high above him and he's standing on tiptoe to keep his fragile wrists from needing to support his full weight.

Slim walks a circle around Geno, eyeing his posture carefully, "Painful?"

"No, sir."

"Comfortable?"

Geno wiggles in the cuffs a little, and cringes, "N-no, sir."

"Perfect." Seeming satisfied, Slim beckons to Hacker, "You'll want to be closer for this."

Hacker steps forwards with a trembling soul to stand before his immobilized boyfriend. Geno can't look him in the eyelights, but he does keep casting quick glances at him. Slim brings over the whip and sets it in Hacker's hands. The change is immediate- the second the threatening toy is in sight, Geno shudders hard again, letting out a little gasping breath as his red magic forms a girthy cock at his crotch. Stretch whistles appreciatively, coming to stand beside Hacker.

"Not bad. Must take some work to be able to have that inside you."

Hacker blushes, his two-tone magic turning his face blue and green at the same time, "I-it does, yeah... Feels good, though. Every time."

"I don't doubt it."

Geno squirms what little he can under Stretch's eye. Slim snorts and takes Hacker by the hand. They walk around Geno's blind side- a bit of intentional cruelty, Hacker suspects- to stand behind him. Hacker admires the gentle curve of Geno's spine, the tiny scars and discolorations coating every rib. He gets so distracted that Slim's voice startles him.

"Hit him."

"Wh-what?!" Hacker's first reaction is panic, "I can't just-!"

"Geno," Slim asks again, "Do you enjoy pain?"

"Yes, sir." There's no hesitation, and the fear seems to have been overtaken by excitement.

"Do you want Hacker to hurt you?"

"Yes, sir. Please."

That little breathy plea makes Hacker's soul twist. If it's what Geno really wants, then Hacker will do it.

"Hit him," Slim repeats, "Hard as you can stand to."

Hacker takes a steadying breath and raises the whip, but Slim takes his wrist with a sigh.

"Sorry. Should have taught you how to use it, first."

Slim's long fingers cover Hacker's hand and guide him in the proper swing. Even with as slowly as they move, the end of the whip still makes a _snap!_ as it connects with a rib. Geno twitches and lets out a tiny gasp. Slim steps back again and motions for Hacker to try again. This time, Hacker gets a bit more momentum behind it. The sound of the hit is louder, as is the sound Geno makes in response. Slim tuts.

"You're gonna have to hit harder than that."

"What?" Hacker's soul drops, "I already feel like I'm being cruel."

Slim sighs, "Geno. Do you enjoy pain?"

"Yes, sir."

"Do you want to be hit harder?"

"Yes, please, sir."

Slim looks pointedly at Hacker. The tiny skeleton musters as much strength as he can and swings the whip again. This time, Geno makes a small moan at the contact. But Slim still looks unsatisfied. He takes the whip from Hacker.

"Go back and stand with Stretch. You need to see this."

"Okay...?"

Puzzled and disappointed in his failure, Hacker steps around Geno's good eye this time, daring a glance up. Geno is watching him with a heated gaze, his face burning brightly. The expression makes Hacker's magic rev again, threatening to form an entrance to be ravaged. Stretch catches him by the hand and pulls him in front.

"Watch his face."

Hacker nods slowly, wondering where this is going. He sees movement through Geno's ribs and realizes with a jolt that Slim's going to hit Geno way harder than Hacker ever would.

"Wait-!"

He's too late. The whip makes a loud _crack!_ as it connects with the back of Geno's ribcage. But even louder is the sound Geno makes- a yelp that smoothes into an appreciative moan. His expression isn't pained at all. In fact, he appears to have really enjoyed that.

"Oh," is all Hacker can say. It makes Stretch chuckle.

Slim winds up again and brings the whip down even harder. Geno jolts in his bonds, a shout escaping before becoming another moan. That does it- Hacker's magic forms in his tight pants, already wet and hopeful. But Slim isn't done. Hacker watches in horror as the lanky skeleton uses his whole body length to really accelerate the bit of leather. This time, Geno's scream is just pain and no pleasure. He squeezes his eyesocket shut against brimming tears.

"There." Stretch is watching over Hacker's head, "That's his limit. Did you hear it? There was no moan that time. Hit him that hard too much, and he'll safeword." He casts a pointed look at the bound skeleton, "He'd better."

Geno shudders, his voice trembling now, "Y-yes, sir."

Slim huffs a satisfied breath from behind Geno, "Do you see now? What you were doing was teasing him. He _wants_ more pain than what you were giving." As Hacker nods slowly, the weight of those words sinking in, Slim offers, "Do you want to try again?"

Hacker's first instinct is to say no- he doesn't want to hurt his lover. Geno is always so careful and gentle with him, it seems wrong to be so rough in return. But Geno reopens his eye, the light within seeking out direct contact with Hacker's own, and he whispers a request so honest, Hacker's soul trembles.

"Please, my goddess. I want this."

Hacker can't say no to that. He at least owes it to Geno to try once more before setting aside forever a kink that Geno obviously greatly enjoys. He heads back around to take the whip from Slim. He runs a thumb over the wrapped leather handle, feels the weight of the trailing tip tugging his hand toward the ground. He takes a breath and lets it out slowly. He can do this. He can make Geno moan like that again.

Hacker hits Geno hard, earning himself a yelp and a whimper. It's not as loud as it should be, though. Hacker hauls off and hits his lover as hard as he can. The resulting scream warbles into a moan. That was it. That's the sweet spot. Hacker gives him another, and another, and another. He finds that if he spaces them just right, Geno will cut off his moan with the next yell. And if he goes fast enough, Geno starts to squirm in his bonds. But Hacker's arm is getting tired from the shoulderblade all the way down through his fingertips. Who knew whipping someone was such hard work?

Slim gives Hacker a knowing smile, "Want to go play with Stretch while I take over?"

Hacker isn't sure what he means by that, but he's glad for the reprieve. He hands off the whip and goes to join the other tall monster at Geno's front.

"Here, half-pint," Stretch purrs, "C'mere. I have an idea." He places Hacker diectly in front of Geno and much closer than before. "Tell him what you think of him," Stretch prompts, "how good he's being, how beautiful he looks right now."

Hacker admires his boyfriend, realizing that Stretch is right. Between the beads of sweat rolling off his bones, the scarlet hue of his cheekbones, and the way his tongue is hanging out as he pants, Hacker isn't sure why he was so worried about this to begin with.

"You're such a good boy," he says.

Geno shivers. Stretch motions for Hacker to go on.

"You look so good right now, Geno. So... sexy. And you're so strong." The more he goes on, the more Geno shakes. "You can take so much pain and actually enjoy it. You're really amazing, Geno."

Geno's whole body jerks, frantic whines and whimpers coming unbidden from his mouth.

Stretch chuckles, stepping between them, "Take it easy on him, half-pint. Look what you're doin' to the poor guy."

Confused, Hacker watches Stretch approach and reach out a hand. Geno jolts and gasps as long fingers wrap around his member. Stretch slowly swipes up, collecting all the precum to show to Hacker.

"See all that? All for you, half-pint. You really have him goin'." As Hacker gapes, Stretch grins, "Maybe I should give him a little reprieve?"

He drops to his knees. It takes Hacker a minute to process what's about to happen. When he does, he takes an unconscious step to the side for a better view as Stretch opens his mouth wide and takes in Geno's head. The bound skeleton gasps and tries to thrust his hips forward, but he can't get enough purchase on the ground with his arms bound and his feet up on tiptoe as they are. His squirming seems to amuse Stretch, as the lazy monster moves deeper only in milimeters. Geno thrashes above him, whimpering and nearly sobbing at the stimulation. It's not enough and all too much at the same time.

Hacker slips a hand into his waistband. There's something enthralling about watching someone else give his lover a blowjob. Stretch takes his time, intentionally drawing it out. Geno starts to beg, tears gathering in his good socket again.

"Please, please, please! I need to cum, just let me, please!"

Slim snorts, drawing Hacker's attention, "Your call, half-pint. Has he earned a reward?"

Hacker turns back to Geno to admire his facial expression a moment longer before responding, "Yes. Good boy, Geno."

As Hacker drops his sneaky praise, Stretch suddenly swallows the thick cock completely. Geno convulses with a choke. To top it off, Slim starts whipping him again, too. Geno's cries are so loud and frenzied they almost sound like manic laughter at times. Still, Hacker is hypnotized watching Stretch's head bob, the scarlet shaft disappearing and reappearing rapidly. Geno goes higher on his toes, his hands clenching into fists and his eyesocket squeezing shut. His mouth is moving like he's still trying to yell, but he's not making any sound. It lasts for a few seconds straight before Slim and Stretch both let up simultaneously. Stretch pulls back, lapping a long orange tongue around his mouth to scoop up every drop of Geno's release while Slim growls with satisfaction and possessiveness.

Hacker wiggles, stifling a needy whine. He was getting close himself watching the threesome go and touching his now soaked slit. The tall duo notices his discomfort with twin smirks. Slim steps close to caress the marks on Geno's back, his fingertips coming away red here and there. He whispers into the side of Geno's skull.

"You see your cute little goddess over there? He got himself all excited watching you." Geno whimpers, apparently still unable to speak. Slim chuckles, "Do you want to do something about it? Maybe fuck him hard and deep with that sweet cock of yours?"

Geno whines, pants, and manages to choke, "Y-ye-yesss, sir, ple-please!"

Stretch crooks a finger at Hacker. As the tiny skeleton steps closer, Slim yanks Geno's chin over to shove his burnt orange tongue into the open, panting mouth. Geno squirms beneath him for a second before relaxing and letting him take over. Hacker finds it hot, watching someone else ravage Geno's mouth. From his shorter vantage point, he can actually see Slim's dark orange appendage invading and tangling with Geno's bright red. Hacker wiggles again with want.

Stretch takes advantage of his distraction to strip off Hacker's pants. The cool air on the already sensitive ecto makes Hacker shiver a bit as he steps out of the restricting clothing with Stretch's help. The other skeleton places a cheeky kiss on the inside of Hacker's femur.

"Go get 'em, half-pint."

Slim is lowering Geno to the ground. Spent and shaky as the king is, his legs crumple beneath him. Slim doesn't seem to mind, rearranging him to sit cross-legged on the floor. The more experienced dom beckons Hacker again.

"Why don't you come sit in your lover's lap for a bit?"

The wink is unnecessary; Hacker already knows what he means. He wraps his arms loosely around Geno's shoulders, feeling the numerous hot spots the whip left behind, and slowly sinks down on Geno's revived member. Hacker finds himself thanking his lucky stars that they had sex just the previous night. Otherwise, they'd have to do the whole ritual of stretching his hole and easing him into it. At least he doesn't have to worry about lubrication- watching the other couple play with Geno has left Hacker dripping and eager for penetration. With a little effort and a small gasp of pain, he settles all the way down onto Geno's femurs in one motion. Two voices harmonize in a low moan. Hacker looks up into Geno's single eyelight, willing his expession to tell his beloved boyfriend how much he loves this feeling of being full. Geno shivers again. Message received.

"Well?" Stretch drawls, amusement clear in his tone, "You just gonna' sit on him or what?"

Hacker's face burns. He had forgotten they had an audience. He pushes himself up and drops back down, keeping each motion slow and controlled. Geno groans beneath him, his arms shaking.

Slim hums, "If I release his wrists, he's probably going to grab onto you. That alright?"

"Y-yes!" An accidentally fast drop makes Hacker's answer into a gasp. It makes Slim chuckle as he crouches behind Geno.

Within a few seconds, Geno's arms are around the tiny skeleton, warm and safe as always. Geno buries his face in Hacker's neck, whispering to him with voice trembling still.

"I love you... My Hacker, my goddess... I love you so much..."

His hands grip Hacker's hips, helping him deepen and speed up their lovemaking. Hacker sighs with pleasure.

"G-Geno! I'm so close!"

His lover presses a kiss into the tip of his shoulderblade, "Please?"

That does it; that small request tips Hacker over the edge. He thows his head skyward, back arching as he lets out a luxurious moan. He feels Geno's breath hitch under him, a telltale sign of his boyfriend's climax. He does his best to keep moving through his own orgasm to make sure Geno gets to fully complete his. Then, they both slow to a stop, and Hacker leans forward to pull Geno into a soft and chaste kiss.

"Aww, ain't that sweet." The languid drawl does nothing to discourage their loving gesture this time. Strech turns to eye his own boyfriend, "Shall we go play a game on our own?"

Slim's chuckle is all the answer he needs. But the tallest monster stops to pet Hacker's skull on the way out, "Remember what I told you about aftercare. And his back will need healed or at least washed before you settle in for the night."

This time, it's Hacker who answers with a "Yes, sir."

"And watch him for sub drop. That was a pretty intense session; he's probably going to feel dirty afterward. He's already inclined towards self-hate, so it might take a few days before he's completely okay again. If you're worried or you need help, come find me or Stretch."

Again, "Yes, sir."

A soft _pop_ announces the other couple's departure. Hacker gently tugs on Geno's shoulders and ribs until he coaxes the much broader frame to lie down with him. Curled on their sides, their limbs tangle together. Hacker reaches for the phrase Slim taught him.

"What do you need, Geno?"

"You," Geno answers with a contented sigh, "This. Just you."

Hacker is more than happy to oblige.


End file.
